Barrel mounting



April 4, 1944; s, G. GREEN 2,345,596

BARREL MOI'JNTING Filed July 8, 1940 EFL INVENTOR 3 W 511m. a1. .5. Err EEJ'L av 88/54 M ATTORNEYS Patented Apr. 4-, 1944 UNITED STATES @ATENT OFFICE (Granted under the act of March 3, 1883, as amended April 30, l928; 3'70 0. G. 757) 4 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to means for mounting the muzzle end portion of an air cooled gun barrel, and is particularly adapted for use in fixed aircraft and similar fixed vehicular mounts where a blast tube is used to conduct the gases of explosion arising from firing through the cowling of the aircraft or othervehicle.

It is an object of the invention to so mount the muzzle end portion of the barrel of an automatic fixed gun in a blast tube that frequent dismounting for cleaning will be obviated.

It is a further object of the invention to mount the muzzle end portion of the barrel of an automatic fixed gun in a blast tube in a manner to positively preclude travel of gases between the barrel and blast tube rearwardly from the muzzle of the latter.

A still further object of the invention is to so mount the muzzle portion of the barrel of an automatic gun in a blast tube as to utilize the flow of gases under high velocity from the muzzle of the barrel to withdraw gases accumulating rearwardly of the muzzle between the barrel and blast tube, in a manner similar to the manner in which an injector functions.

In view of the relative high speeds at which present day aircraft travel; the long leads of the blast tubes necessary in the fixed installation of automatic guns on such craft; the intricacies of the fixed type of installation on such aircraft, which renders accessibility difficulty with frequent dismounting of the gun consequently rendered impractical; and the present increased gun firing rates, it has become imperative that the muzzle end bearing of the gun barrel be substantially self cleaning and lubricating, to obviate the necessity of frequent dismounting of the gun for cleaning; and that fiow of gases rearwardly between the barrel and blast tube to the gunners cockpit or similar station be prevented to eliminate placing the gunner under this handicap. Therefore, with these factors in mind it is a still further object of the invention to provide barrel mounting for the muzzle end portion of the barrel of an automatic fixed mount gun that will in practice overcome the difiiculties introduced by these factors.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodi ment as shown in the accompanying drawings in which:

Fig. 1 is a longitudinal sectional view through the muzzle end portion of the barrel of an automatic gun of the type wherein the barrel has limited recoil and counterrecoil movement mounted in a blast tube also shown in fragmentary longitudinal section.

Fig. 2 is a view similar to- Fig. 1 showing a slight modification.

Fig. 3 is sectional view showing a modification;

Fig. 4 is a sectional View showing a modified barrel wherein the use of a separate bearing and guide sleeve is eliminated.

Referring now to the drawing there is shown a barrel l9 suitably mounted for limited recoil and counter-recoil movement as is Well known in the art. The barrel II] is mounted within a stationary barrel jacket I i and is guided in recoil and counterrecoil movements adjacent its muzzle end by a cylindrical guide sleeve l2 suitably secured to the barrel in fluid sealed relation adjacent its forward end in such manner as to increase the effective cross sectional area of the forward end of the barrel. From its zone of attachment to the barrel the sleeve I2 extends rearwardly in circumferentially spaced relation to the barrel a suitable distance where it is terminated in an inwardly directed flange it which engages the barrel I 0.

A cylindrical acceleration chamber forming member I4 is secured to the forward end of the barrel jacket II in axial prolongation thereof in any convenient manner and has its rear portlon protruding within the muzzle end portion of the barrel jacket II. The forward end portlon of the sleeve I2 is externally reduced to form a seat for a bearing broaching ring 55 which may be preformed to fit the seat in the sleeve IE or cast or deposited thereon as found most expedient and a cooperating bearing broaching ring it is provided Within the member 1 4 adapted by its configuration to cooperate with the bearing breaching ring IS in clearing the bearing surfaces between these two rings of deposits tending to collect thereon. Forwardly of the bearing broaching ring it a plug ll having an axial projectile passage is is inserted Within the member I i and is designed to so constrict the forward end of the member I 4 as to form a barrel accelerator or booster chamber i9. Gases passing from the chamber I9 rearwardly past the rings 15-16 are emitted from within the member 14 by way of ports 29. The structo provide a plurality of longitudinally spaced grooves 22 which act in combination with the bearing surface on sleeve I2 to form a tortuous passage from one side of the bearingring 2| to the other and thereby effectively prevent the flow of gases through the bearing between the sleeve |2 and member I4.

The blast tube 23 is of substantially the same inside diameter as the outside diameter of the barrel jacket so as to snugly receive the latter and to further perfect the seal between the blast tube and barrel jacket a gasket G of any desirable material such as asbestos, is inserted between the blast tube and barrel jacket.

The sleeve I2, bearing broaching rings I5, I6, member Hi and bearing ring 2| may all be made of the same materials as suggested for the comparable parts in my copending applications above referred to.

In order to prevent injury to the bearing ring 2| by the relative hard'broaching ring I when the barrel III is withdrawn from or inserted within the barrel jacket II and member I4 the sleeve I2 is formed to provide an annular ramp surface 24 which is so proportioned as to coact with a ramp surface 25 on member I4 in such manner as to ensure that the bearing breaching ring I5 will be substantially centered with respect to the member I4 and bearing ring 2| as the barrel muzzle portion is inserted within the member III. It will of course :be understood that the ramp surfaces 24 and 25 are so related as to prevent the barrel from becoming eccentric to such an extent with respect to the bearing 2| and member I4 that the broaching ring I5 can contact bearing 2| before the broaching ring I5 clears the bearing ring 2| upon withdrawal of the barrel from member I4.

In operation the accelerator chamber I9 will cause the gases of explosion to accelerate recoil of the barrel and a portion of the gases will es cape past the bearing broaching rings I5, I5 which have a working clearance of one to four times as great as the working clearance between the :bearing ring 2| and sleeve I2. Gases escaping past the rings I5 and IE will be emitted from member I4 through the ports 20 located intermediate the rings I5, I6 and ring 2| into the annular space between the exterior of member I4 and interior of the blast tube 23. Because of the very accurate fit of bearing ring 2| with sleeve I2 and the construction of the ring the escape of gases past the ring 2| between its bearing with sleeve I2 is practically .precluded. Likewise escape of gases rearwardly between the barrel jacket II and blast tube 23 is precluded by the accurately interfitted relation of these members and the interposition of the gasket G therebetween. Emission of gases at a high velocity from the projectile passage IS in plug creates a region of lower pressure axially of the blast tube and consequently gases under reduced velocity head and accompanying increased pressure head, such as the gases emitted from ports 2!], are forced to travel to the axial region of lower pressure where they escape from the blast tube. This application of the injector principle is advantageously employed in the instant case as it provides a path of ready escape for the gases which escape rearwardly past the rings I5 and I6 for zle of the gun and is mounted in a high speed plane.

In the modification shown in Fig. 2 the sleeve I2 is secured to the barrel adjacent its forward end portion in the same manner as in Fig. 1, however, in this form of the invention the bearing element 5' is conveniently made integral with the sleeve i2 and formed with a cylindrical plane bearing surface I5". Also the flange I 3' of the sleeve is outwardly directed instead of being inwardly directed as in Fig. 1 and terminates in an annular bearing surface l3 which engages the cylindrical member I4 in bearing relation. If desired circumferentially spaced bearing elements 26 may be formed on the'sleeve to engage the barrel to provide a firm support for the sleeve on the barrel. In this manner increased bearing support for the muzzle of the barrel is obtained and circulation of air or other fluid between the sleeve I2 and barrel I ll afforded. Ports 21 may be formed between the flange l3 and bearing 2| to facilitate circulation of air to the bearing surfaces thereon and assist in preventing escape of gases rearwardly past the bearing 2|.

To further increase the efiiciency of the device a suitable gasket may be interposed between the sleeve I2 and member I4 intermediate the flange I3 and bearing 2|, or within an annular groove in bearing surface I3", however, in View of the bearing arrangement of this invention such practice will not be essential in the ordinary mount.

Furthermore the interior of the barrel jacket I may be so treated as to serve as a bearing for flange I3 of sleeve I2 directly, thereby eliminating that portion of member I4 extending rearwardly of bearing 2| as clearly shown in Fig. 3, however, the form shown in Fig. 2 is preferred.

In the presently preferred form of the invention a separate bearing and guide sleeve I2 or I2 is utilized as shown in Figs. 1, 2 and 3, however, if desired the separate sleeve may be eliminated and the muzzle portion of the barrel formed as shown in Fig. 4 so as to be directly received by the bearing ring 2|, which in effect makes the barrel and sleeve integral functionally.

Having now described what is at present con sidered the preferred embodiment of the invention I claim:

1. In a barrel mounting adapted for use in mounting the muzzle end portion of a gun within a blast tube in combination, a barrel jacket, a cylindrical member mounted on the jacket in axial prolongation thereof with its rear portion terminating within the jacket, a bearing ring: provided with interior annular grooves mounted within the rear portion of the member, a bearing breaching ring mounted within the member forwardly of said bearing ring in spaced relation, a barrel mounted within the barrel jacket, a sleeve secured to the barrel in fluid sealed relation adjacent its forward end, said sleeve being disposed within said bearing ring in accurately fitted bear-- ing relation and being provided with a bearing breaching ring disposed in bearing relation with said first recited bearing broaching ring, and said member being formed with ports intermediate said bearing and bearing broaching rings.

2. In a barrel mounting adapted for use in mounting the muzzle end portion of a gun within a blast tube in combination, a barrel jacket, a cylindrical member mounted on the jacket in axial prolongation thereof with its rear portion terminating within the jacket in an annular ramp surface, a bearing ring provided with interior annular grooves mounted within the rear portion of the member, a bearing broaching ring mounted within the member in forwardly spaced relation to said bearing ring, a removably mounted barrel mounted within the jacket, a sleeve secured to the barrel in fluid sealed relation adjacent its forward end and having a bearing portion extending rearwardly of the barrel in circumferentially spaced relation thereto, said sleeve being formed with a ramp surface intermediate its bearing portion and forward end portion adapted to cooperate with said first named ramp surface in centering the barrel relative to said member when interengaged, said barrel being mounted with the bearing portion of its sleeve disposed in accurately fitted bearing relation within said bearing ring, a cooperating bearing broaching ring provided on the forward end portion of said sleeve disposed Within said first recited bearing broaching ring and having a working clearance of one to four times the clearance of the sleeve and bearing ring, and gas emission ports provided in ,said member intermediate the bearing and bearing broaching rings.

3. The structure of claim 2 in combination with a blast tube fitted in close engagement around said barrel jacket and pro ecting forwardly of the cylindrical member, and wherein said cylindrical member is of smaller diameter externally than the internal diameter of the blast tube.

4'. The structure of claim 2 in combination with a blast tube fitted in close engagement around said barrel jacket and projecting forward- 1y of the cylindrical member, gasket means interposed between said barrel jacket and blast tube and wherein said cylindrical member is of smaller diameter externally than the internal diameter of the blast tube.

SAMUEL G. GREEN. 

